Injection molding is widely used method of manufacturing plastic parts for modern devices such as portable electronic devices. Injection molding techniques can produce high volumes of the same object in a cost effective manner. Thermoplastic and thermosetting polymers are widely used in injection molding. Common polymers like epoxy and phenolic resin are examples of thermosetting plastics while nylon, polyethylene, and polystyrene are common thermoplastics.
Portable electronic devices have become popular in recent years. These devices have become a mainstay in society and are used for communication, information and entertainment. In some ways portable electronic devices have become a status symbol and users want them to be aesthetically pleasing as well as functional. Because users carry these devices throughout the day and in many environments, the devices must be durable as well as functional and aesthetically pleasing.
In many instances, portable electronic devices include housings or other components which are durable and can withstand the environmental conditions as well as the stress and strain imposed as a result of user activities and, in some cases, abuse.
In some portable electronic devices, thermoplastic components may be molded directly onto metal surfaces to provide waterproofing as well as decorative and aesthetically pleasing surfaces on the device. Waterproof thermoplastic surfaces do not rust or corrode and thus are preferred over some metal surfaces which may not be as resistant to these elements. In addition, in order to protect the metal surface and certain electronic components, a watertight seal may be desirable between the thermoplastic material layer and the metal housing of the device.